Distending portion for intraocular lens system

ABSTRACT

There is disclosed an accommodating intraocular lens for implantation in an eye having an optical axis. The lens comprises an anterior portion which in turn comprises an anterior viewing element and an anterior biasing element. The lens further comprises a posterior portion which in turn comprises a posterior viewing element in spaced relationship to the anterior viewing element and a posterior biasing element. The anterior portion and posterior portion meet at first and second apices of the intraocular lens. The anterior portion and the posterior portion and/or the apices are responsive to force thereon to cause the separation between the viewing elements to change. Additional embodiments and methods are also disclosed.

RELATED APPLICATIONS

[0001] The present application claims the benefit of U.S. ProvisionalPatent Application No. [Attorney Docket No. VGEN.001PR2], filed Nov. 9,2001 and titled ACCOMMODATING INTRAOCULAR LENS SYSTEM; and of U.S.Provisional Patent Application No. 60/264,179, filed Jan. 25, 2001 andtitled ACCOMMODATING INTRAOCULAR LENS SYSTEM; and of U.S. ProvisionalPatent Application No. 60/283,856, filed Apr. 13, 2001 and titledACCOMMODATING INTRAOCULAR LENS SYSTEM. The entire disclosure of allthese provisional patent applications is incorporated by referenceherein and made a part of this specification.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates to intraocular lenses and, moreparticularly, to intraocular lenses that alter the refractive power ofthe eye in response to changes in the tension of the ciliary muscle ofthe eye.

[0004] 2. Description of the Related Art

[0005] The vast majority of cataract operations involve the implantationof an artificial lens following cataract removal. Typically these lenseshave a fixed focal length or, in the case of bifocal or multifocallenses, have several different fixed focal lengths. Such fixedfocal-length lenses lack the ability of the natural lens to dynamicallychange the refractive power of the eye. The various embodiments of theintraocular lens disclosed herein provide an accommodating lens systemwhich alters the refractive power of the eye in response to changes intension of the ciliary muscle, thereby allowing the lens system to bringinto focus on the retina images of objects that are both near and farfrom the eye.

SUMMARY OF THE INVENTION

[0006] One aspect of the invention is an accommodating intraocular lensfor implantation in an eye having an optical axis. The lens comprises ananterior portion which in turn comprises an anterior viewing elementcomprised of an optic having refractive power and an anterior biasingelement comprising first and second anterior translation membersextending from the anterior viewing element. The lens further comprisesa posterior portion which in turn comprises a posterior viewing elementin spaced relationship to the anterior viewing element and a posteriorbiasing element comprising first and second posterior translationmembers extending from the posterior viewing element. The anteriorportion and posterior portion meet at first and second apices of theintraocular lens such that a plane perpendicular to the optical axis andpassing through the apices is closer to one of said viewing elementsthan to the other of said viewing elements. The anterior portion and theposterior portion are responsive to force thereon to cause theseparation between the viewing elements to change.

[0007] Another aspect of the invention is an accommodating intraocularlens for implantation in an eye having an optical axis. The lenscomprises an anterior portion, which in turn comprises an anteriorviewing element comprised of an optic having refractive power, and ananterior biasing element comprising first and second anteriortranslation members extending from the anterior viewing element. Thelens further comprises a posterior portion which in turn comprises aposterior viewing element in spaced relationship to the anterior viewingelement, and a posterior biasing element comprising first and secondposterior translation members extending from the posterior viewingelement. The anterior portion and posterior portion meet at first andsecond apices of the intraocular lens. The anterior portion and theposterior portion are responsive to force thereon to cause theseparation between the viewing elements to change. The first anteriortranslation member forms a first anterior biasing angle, as the lens isviewed from the side, with respect to a plane perpendicular to theoptical axis and passing through the apices. The first posteriortranslation member forms a first posterior biasing angle, as the lens isviewed from the side, with respect to the plane. The first anteriorbiasing angle and the first posterior biasing angle are unequal.

[0008] Another aspect of the invention is an accommodating intraocularlens comprising an anterior viewing element comprised of an optic havingrefractive power of less than 55 diopters and a posterior viewingelement comprised of an optic having refractive power. The opticsprovide a combined power of 15-25 diopters and are mounted to moverelative to each other along the optical axis in response to acontractile force by the ciliary muscle of the eye upon the capsular bagof the eye. The relative movement corresponds to change in the combinedpower of the optics of at least one diopter. Alternatively, theaccommodating intraocular lens can further comprise a posterior viewingelement comprised of an optic having a refractive power of zero to minus25 diopters.

[0009] A further aspect of the invention is an accommodating intraocularlens comprising an anterior portion which in turn comprises an anteriorviewing element which has a periphery and is comprised of an optichaving refractive power. The anterior portion further comprises ananterior biasing element comprising first and second anteriortranslation members extending from the anterior viewing element. Thelens further comprises a posterior portion which in turn comprises aposterior viewing element having a periphery, the posterior viewingelement being in spaced relationship to the anterior viewing element,and a posterior biasing element comprising first and second posteriortranslation members extending from the posterior viewing element. Thefirst anterior translation member and the first posterior translationmember meet at a first apex of the intraocular lens, and the secondanterior translation member and the second posterior translation membermeet at a second apex of the intraocular lens, such that force on theanterior portion and the posterior portion causes the separation betweenthe viewing elements to change. Each of the translation members isattached to one of the viewing elements at at least one attachmentlocation. All of the attachment locations are further away from theapices than the peripheries of the viewing elements are from the apices.

[0010] A further aspect of the invention is an accommodating intraocularlens comprising an anterior portion comprised of a viewing element. Theviewing element is comprised of an optic having refractive power. Thelens further comprises a posterior portion comprised of a viewingelement. The viewing elements are mounted to move relative to each otheralong the optical axis in response to force generated by the ciliarymuscle of the eye. The lens further comprises a distending portioncomprised of a distending member having a fixed end attached to theposterior portion and a free end sized and oriented to distend a portionof the lens capsule such that coupling of forces between the lenscapsule and the intraocular lens is modified by the distending portion.

[0011] A further aspect of the invention is an accommodating intraocularlens. The lens comprises an anterior portion comprised of an anteriorviewing element and an anterior biasing element connected to theanterior viewing element. The anterior viewing element is comprised ofan optic having refractive power. The lens further comprises a posteriorportion comprised of a posterior viewing element and a posterior biasingelement connected to the posterior viewing element. The lens has anoptical axis which is adapted to be substantially coincident with theoptical axis of the eye upon implantation of the lens. The anterior andposterior viewing elements are mounted to move relative to each otheralong the optical axis in response to force generated by the ciliarymuscle of the eye. The biasing elements are joined at first and secondapices which are spaced from the optical axis of the lens. The lensfurther comprises a distending member extending between the first andsecond apices.

[0012] A further aspect of the invention is an accommodating intraocularlens comprising an anterior portion comprised of a viewing element. Theviewing element is comprised of an optic having refractive power. Thelens further comprises a posterior portion comprised of a viewingelement. The viewing elements are mounted to move relative to each otheralong the optical axis in response to force generated by the ciliarymuscle of the eye. The lens further comprises a retention portioncomprised of a retention member having a fixed end attached to theanterior portion and a free end sized and oriented to contact a portionof the lens capsule such that extrusion of the implanted lens throughthe lens capsule opening is inhibited.

[0013] A further aspect of the invention is an accommodating intraocularlens. The lens comprises an anterior portion comprised of a viewingelement, the viewing element comprised of an optic having refractivepower, and a posterior portion comprised of a viewing element. Theviewing elements are mounted to move relative to each other along theoptical axis in response to force generated by the ciliary muscle of theeye. The lens further comprises a distending portion comprised of adistending member attached to one of the portions, and oriented todistend the lens capsule such that the distance between a posterior sideof the posterior viewing element and an anterior side of the anteriorviewing element along the optical axis is less than 3 mm when theciliary muscle is relaxed and the lens is in an unaccommodated state.

[0014] A further aspect of the invention is an accommodating intraocularlens. The lens comprises an anterior portion comprised of a viewingelement, the viewing element comprised of an optic having refractivepower, and a posterior portion comprised of a viewing element. Theviewing elements are mounted to move relative to each other along theoptical axis in response to force generated by the ciliary muscle of theeye. The lens further comprises a distending portion comprised of adistending member attached to one of the portions, and oriented todistend the lens capsule. The distending causes the lens capsule to acton at least one of the posterior and anterior portions such thatseparation between the viewing elements is reduced when the ciliarymuscle is relaxed and the lens is in an unaccommodated state.

[0015] A further aspect of the invention is an accommodating intraocularlens. The lens comprises an anterior portion comprised of a viewingelement, the viewing element comprised of an optic having refractivepower, and a posterior portion comprised of a viewing element. Theviewing elements are mounted to move relative to each other along theoptical axis in response to force generated by the ciliary muscle of theeye. The lens further comprises a distending member attached to theposterior portion. The distending member is separate from the biasingmembers and reshapes the lens capsule such that force coupling betweenthe ciliary muscle and the lens is modified to provide greater relativemovement between the viewing elements when the lens moves between anunaccommodated state and an accommodated state in response to theciliary muscle.

[0016] A further aspect of the invention is an accommodating intraocularlens. The lens comprises an anterior portion comprised of an anteriorviewing element and an anterior biasing element connected to theanterior viewing element, the anterior viewing element being comprisedof an optic having refractive power. The lens further comprises aposterior portion comprised of a posterior viewing element and aposterior biasing element connected to the posterior viewing element.The lens has an optical axis which is adapted to be substantiallycoincident with the optical axis of the eye upon implantation of thelens. The anterior and posterior viewing elements are mounted to moverelative to each other along the optical axis in response to forcegenerated by the ciliary muscle of the eye. The biasing elements arejoined at first and second apices which are spaced from the optical axisof the lens. The lens further comprises first and second distendingmembers. Each of the members is attached to one of the anterior andposterior portions and extends away from the optical axis. The firstmember is disposed between the apices on one side of the intraocularlens and the second member is disposed between the apices on theopposite side of the intraocular lens. The distending members areoriented to distend portions of the lens capsule such that the viewingelements are relatively movable through a range of at least 1.0 mm inresponse to contraction of the ciliary muscle.

[0017] A further aspect of the invention is an accommodating intraocularlens comprising an anterior portion which is in turn comprised of aviewing element. The anterior viewing element is comprised of an optichaving a diameter of approximately 3 mm or less and a refractive powerof less than 55 diopters. The lens further comprises a posterior portioncomprised of a viewing element. The viewing elements are mounted to moverelative to each other along the optical axis in response to forcegenerated by the ciliary muscle of the eye. The lens further comprises adistending portion comprised of a distending member having a fixed endattached to the posterior portion and a free end sized and oriented todistend a portion of the lens capsule such that coupling of forcesbetween the lens capsule and the intraocular lens is increased.

[0018] A further aspect of the invention is an accommodating intraocularlens. The lens comprises an anterior portion comprised of a viewingelement, the anterior viewing element being comprised of an optic havinga refractive portion with a refractive power of less than 55 diopters.The lens further comprises a posterior portion comprised of a viewingelement. The lens has an optical axis which is adapted to besubstantially coincident with the optical axis of the eye uponimplantation of the lens. The posterior viewing element comprises anoptic arranged substantially coaxially with the anterior optic on theoptical axis of the lens. The posterior optic has a larger diameter thanthe refractive portion of the anterior optic. The posterior opticcomprises a peripheral portion having positive refractive power andextending radially away from the optical axis of the lens beyond theperiphery of the refractive portion of the anterior optic, so that atleast a portion of the light rays incident upon the posterior optic canbypass the refractive portion of the anterior optic.

[0019] A further aspect of the invention is an accommodating intraocularlens. The lens comprises an anterior portion comprised of a viewingelement, the anterior viewing element being comprised of an optic havinga refractive power of less than 55 diopters. The lens further comprisesa posterior portion comprised of a viewing element. The lens has anoptical axis which is adapted to be substantially coincident with theoptical axis of the eye upon implantation of the lens. The posteriorviewing element comprises an optic arranged substantially coaxially withthe anterior optic on the optical axis of the lens. The posterior optichas a larger diameter than the anterior optic. The posterior opticcomprises a peripheral portion having positive refractive power andextending radially away from the optical axis of the lens beyond theperiphery of the anterior optic, so that at least a portion of the lightrays incident upon the posterior optic can bypass the anterior optic.

[0020] A further aspect of the invention is an intraocular lens. Thelens comprises an optic and a pair of elongate members extending fromthe optic. The members are comprised of a shape memory alloy.

[0021] A further aspect of the invention is an accommodating intraocularlens for implantation in an eye having an optical axis and a lenscapsule having a capsule opening for receiving the lens. The lenscomprises a posterior portion comprised of a posterior viewing element,and an anterior portion comprised of an anterior viewing element. Theanterior viewing element is comprised of an optic having refractivepower. The viewing elements are mounted to move relative to each otheralong the optical axis in response to force generated by the ciliarymuscle of the eye. The anterior portion is adapted to contact portionsof the lens capsule while being spaced from the lens capsule in at leastone location so as to provide a fluid flow channel that extends from aregion between the viewing elements to a region outside the capsule.

[0022] A further aspect of the invention is an accommodating intraocularlens. The lens comprises an anterior portion which in turn comprises ananterior viewing element having a periphery and comprised of an optichaving refractive power, and an anterior biasing element comprising atleast one anterior translation member attached to a first attachmentarea on the periphery of the anterior viewing element. The firstattachment area has a thickness in a direction substantiallyperpendicular to the periphery and a width in a direction substantiallyparallel to the periphery. The ratio of the width to the thickness isequal to or greater than 3.

[0023] A further aspect of the invention is a method of manufacturing anintraocular lens having anterior and posterior viewing elements arrangedalong a common optical axis. The method comprises defining an anteriorviewing element mold space and a posterior viewing element mold space,arranging the anterior viewing element mold space and the posteriorviewing element mold space along a mold axis substantially coincidentwith the optical axis of the lens, and molding the anterior viewingelement in the anterior viewing element mold space while the anteriorviewing element mold space and the posterior viewing element mold spaceare arranged substantially along the mold axis.

[0024] All of these embodiments are intended to be within the scope ofthe invention herein disclosed. These and other embodiments of theinvention will become readily apparent to those skilled in the art fromthe following detailed description of the preferred embodiments havingreference to the attached figures, the invention not being limited toany particular preferred embodiment(s) disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Having thus summarized the general nature of the invention,certain preferred embodiments and modifications thereof will becomeapparent to those skilled in the art from the detailed descriptionherein having reference to the figures that follow, of which:

[0026]FIG. 1 is a sectional view of the human eye, with the lens in theunaccommodated state.

[0027]FIG. 2 is a sectional view of the human eye, with the lens in theaccommodated state.

[0028]FIG. 3 is a perspective view of one embodiment of an intraocularlens system.

[0029]FIG. 4 is a side view of the lens system.

[0030]FIG. 5 is a rear perspective view of the lens system.

[0031]FIG. 6 is a front view of the lens system.

[0032]FIG. 7 is a rear view of the lens system.

[0033]FIG. 8 is a top view of the lens system.

[0034]FIG. 9 is a side sectional view of the lens system.

[0035]FIG. 10 is a top sectional view of the lens system.

[0036]FIG. 11 is a second perspective view of the lens system.

[0037]FIG. 12 is a third perspective view of the lens system.

[0038]FIG. 13 is a side view of the lens system in the unaccommodatedstate.

[0039]FIG. 14 is a side sectional view of the lens system in theunaccommodated state.

[0040]FIG. 15 is a top sectional view of the lens system in theunaccommodated state.

[0041]FIG. 16 is a sectional view of the human eye with the lens systemimplanted in the capsular bag and the lens system in the accommodatedstate.

[0042]FIG. 17 is a sectional view of the human eye with the lens systemimplanted in the capsular bag and the lens system in the unaccommodatedstate.

[0043]FIG. 17.1 is a sectional view of an arm of the lens system.

[0044]FIG. 17.2 is a sectional view of another embodiment of the arm ofthe lens system.

[0045]FIG. 17.3 a sectional view of other embodiments of the arm of thelens system.

[0046]FIG. 17.4 is a side sectional view of another embodiment of thelens system.

[0047]FIG. 17.5 is a side sectional view of another embodiment of thelens system.

[0048]FIG. 18 is a side view of another embodiment of the lens system.

[0049]FIG. 19 is a side sectional view of another embodiment of the lenssystem.

[0050]FIG. 20 is a rear perspective view of another embodiment of thelens system.

[0051]FIG. 21 is a partial top sectional view of another embodiment ofthe lens system, implanted in the capsular bag.

[0052]FIG. 21.1 is a front view of another embodiment of the lenssystem.

[0053]FIG. 21.2 is a front view of another embodiment of the lenssystem.

[0054]FIG. 21.3 is a front view of another embodiment of the lenssystem.

[0055]FIG. 22 is a partial side sectional view of another embodiment ofthe lens system, implanted in the capsular bag.

[0056]FIG. 22.1 is a side view of a stop member system employed in oneembodiment of the lens system.

[0057]FIG. 23 is a side view of a mold system for forming the lenssystem.

[0058]FIG. 24 is a side sectional view of the mold system.

[0059]FIG. 25 is a perspective view of a first mold portion.

[0060]FIG. 26 is a perspective view of a second mold portion.

[0061]FIG. 27 is a top view of the second mold portion.

[0062]FIG. 28 is a side sectional view of the second mold portion.

[0063]FIG. 29 is another side sectional view of the second mold portion.

[0064]FIG. 30 is a bottom view of a center mold portion.

[0065]FIG. 31 is a top view of the center mold portion.

[0066]FIG. 32 is a sectional view of the center mold portion.

[0067]FIG. 33 is another sectional view of the center mold portion.

[0068]FIG. 34 is a perspective view of the center mold portion.

[0069]FIG. 34.1 is a partial cross sectional view of an apex of the lenssystem, showing a set of expansion grooves formed therein.

[0070]FIG. 35 is a schematic view of another embodiment of the lenssystem.

[0071]FIG. 36 is a schematic view of another embodiment of the lenssystem.

[0072]FIG. 37 is a perspective view of another embodiment of the lenssystem.

[0073]FIG. 38 is a top view of another embodiment of the lens system.

[0074]FIG. 38.1 is a schematic view of another embodiment of the lenssystem, as implanted in the capsular bag.

[0075]FIG. 38.2 is a schematic view of the embodiment of FIG. 38.1, inthe accommodated state.

[0076]FIG. 38.3 is a schematic view of biasers installed in the lenssystem.

[0077]FIG. 38.4 is a schematic view of another type of biasers installedin the lens system.

[0078]FIG. 39 is a series of schematic views of an insertion techniquefor use in connection with the lens system

[0079]FIG. 40 is a schematic view of fluid-flow openings formed in theanterior aspect of the capsular bag.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT I. The Human Eye andAccommodation

[0080]FIGS. 1 and 2 show the human eye 50 in section. Of particularrelevance to the present disclosure are the cornea 52, the iris 54 andthe lens 56, which is situated within the elastic, membranous capsularbag or lens capsule 58. The capsular bag 58 is surrounded by andsuspended within the ciliary muscle 60 by ligament-like structurescalled zonules 62.

[0081] As light enters the eye 50, the cornea 52 and the lens 56cooperate to focus the incoming light and form an image on the retina 64at the rear of the eye, thus facilitating vision. In the process knownas accommodation, the shape of the lens 56 is altered (and itsrefractive properties thereby adjusted) to allow the eye 50 to focus onobjects at varying distances. A typical healthy eye has sufficientaccommodation to enable focused vision of objects ranging in distancefrom infinity (generally defined as over 20 feet from the eye) to verynear (closer than 10 inches).

[0082] The lens 56 has a natural elasticity, and in its relaxed stateassumes a shape that in cross-section resembles a football.Accommodation occurs when the ciliary muscle 60 moves the lens from itsrelaxed or “unaccommodated” state (shown in FIG. 1) to a contracted or“accommodated” state (shown in FIG. 2). Movement of the ciliary muscle60 to the relaxed/unaccommodated state increases tension in the zonules62 and capsular bag 58, which in turn causes the lens 56 to take on athinner (as measured along the optical axis) or taller shape as shown inFIG. 1. In contrast, when the ciliary muscle 60 is in thecontracted/accommodated state, tension in the zonules 62 and capsularbag 58 is decreased and the lens 56 takes on the fatter or shorter shapeshown in FIG. 2. When the ciliary muscles 60 contract and the capsularbag 58 and zonules 62 slacken, some degree of tension is maintained inthe capsular bag 58 and zonules 62.

II. The Lens System: Structure

[0083] FIGS. 3-17 depict one embodiment of an intraocular lens system100 which is configured for implantation into the capsular bag 58 inplace of the natural lens 56, and is further configured to change therefractive properties of the eye in response to the eye's naturalprocess of accommodation. With reference to FIG. 3, a set of axes isincluded to illustrate the sense of directional terminology which willbe used herein to describe various features of the lens system 100. Theterms “anterior” and “posterior” refer to the depicted directions on theoptical axis of the lens 100 shown in FIG. 3. When the lens 100 isimplanted in an eye, the anterior direction extends toward the corneaand the posterior direction extends toward the retina, with the opticalaxis of the lens substantially coincident with the optical axis of theeye shown in FIGS. 1 and 2. The terms “left” and “right” refer to thedirections shown on the lateral axis, which is orthogonal to the opticalaxis. In addition, the terms “upper” and “lower” refer to the directionsdepicted on the transverse axis which is orthogonal to both of theoptical axis and the lateral axis.

[0084] This system of axes is depicted purely to facilitate descriptionherein; thus, it is not intended to limit the possible orientationswhich the lens system 100 may assume during use. For example, the lenssystem 100 may rotate about, or may be displaced along, the optical axisduring use without detracting from the performance of the lens. It isclear that, should the lens system 100 be so rotated about the opticalaxis, the transverse axis may no longer have an upper-lower orientationand the lateral axis may no longer have a left-right orientation, butthe lens system 100 will continue to function as it would when orientedas depicted in FIG. 3. Accordingly, when the terms “upper,” “lower,”“left” or “right” are used in describing features of the lens system100, such use should not be understood to require the described featureto occupy the indicated position at any or all times during use of thelens system 100. Similarly, such use should not be understood to requirethe lens system 100 to maintain the indicated orientation at any or alltimes during use.

[0085] As best seen in FIG. 4, the lens system 100 has an anteriorportion 102 which is anterior or forward of the line A-A (whichrepresents a plane substantially orthogonal to the optical axis andintersecting first and second apices 112, 116) and a posterior portion104 which is posterior or rearward of the line A-A. The anterior portion102 comprises an anterior viewing element 106 and an anterior biasingelement 108. The anterior biasing element 108 in turn comprises a firstanterior translation member 110 which extends from the anterior viewingelement 106 to the first apex 112 and a second anterior translationmember 114 which extends from the anterior viewing element 106 to thesecond apex 116. In the illustrated embodiment the first anteriortranslation member 110 comprises a right arm 110 a and a left arm 110 b(see FIG. 3). In addition, the depicted second anterior translationmember 114 comprises a right arm 114 a and a left arm 114 b. However, inother embodiments either or both of the first and second anteriortranslation members 110, 114 may comprise a single arm or member, ormore than two arms or members.

[0086] As best seen in FIGS. 4, 5 and 7, the posterior portion 104includes a posterior viewing element 118 and a posterior biasing element120. The posterior biasing element 120 includes a first posteriortranslation member 122 extending from the posterior viewing element 118to the first apex 112 and a second posterior translation member 124extending from the posterior viewing element 118 to the second apex 116.In the illustrated embodiment, the first posterior translation membercomprises a right arm 122 a and a left arm 122 b. Likewise, the depictedsecond posterior translation member 124 comprises a right arm 124 a anda left arm 124 b. However, in other embodiments either or both of thefirst and second posterior translation members 122, 124 may comprise asingle arm or member, or more than two arms or members.

[0087] In the embodiment shown in FIG. 4, the anterior biasing element108 and the posterior biasing element are configured symmetrically withrespect to the plane A-A as the lens system 100 is viewed from the side.As used herein to describe the biasing elements 108, 120, “symmetric” or“symmetrically” means that, as the lens system 100 is viewed from theside, the first anterior translation member 110 and the first posteriortranslation member 122 extend from the first apex 112 at substantiallyequal first anterior and posterior biasing angles θ₁, θ₂ with respect tothe line A-A (which, again, represents the edge of a plane which issubstantially orthogonal to the optical axis and intersects the firstand second apices 112, 116) and/or that the second anterior translationmember 114 and the second posterior translation member 124 extend fromthe second apex 116 at substantially equal second anterior and posteriorbiasing angles θ₃, θ₄ with respect to the line A-A. Alternative orasymmetric configurations of the biasing elements are possible, as willbe discussed in further detail below. It should be further noted that asymmetric configuration of the biasing elements 108, 120 does notdictate symmetric positioning of the viewing elements with respect tothe line A-A; in the embodiment shown in FIG. 4 the anterior viewingelement 106 is closer to the line A-A than is the posterior viewingelement.

[0088] Preferably, both the anterior viewing element 106 and theposterior viewing element 118 comprise an optic or lens havingrefractive power. (As used herein, the term “refractive” or “refractivepower” shall include “diffractive” or “diffractive power”.) Thepreferred power ranges for the optics are discussed in detail below. Inalternative embodiments one or both of the anterior and posteriorviewing elements 106, 118 may comprise an optic with a surrounding orpartially surrounding perimeter frame member or members, with some orall of the biasing elements/translation members attached to the framemember(s). As a further alternative, one of the viewing elements 106,118 may comprise a perimeter frame with an open/empty central portion orvoid located on the optical axis (see FIG. 20 and discussion below), ora perimeter frame member or members with a zero-power lens ortransparent member therein. In still further variations, one of theviewing elements 106, 118 may comprise only a zero-power lens ortransparent member.

[0089] In a presently preferred embodiment, a retention portion 126 iscoupled to the anterior portion 102, preferably at the anterior viewingelement 106. The retention portion 126 preferably includes a firstretention member 128 and a second retention member 130, although inalternative embodiments the retention portion 126 may be omittedaltogether, or may comprise only one retention member or more than tworetention members. The first retention member 128 is coupled to theanterior viewing element 106 at a fixed end 128 a and also includes afree end 128 b opposite the fixed end 128 a. Likewise, the secondretention member 130 includes a fixed end 130 a and a free end 130 b.The retention members 128, 130 are illustrated as being coupled to theanterior viewing element 106 at the upper and lower edges thereof;however, the retention members 128, 130 may alternatively be attached tothe anterior viewing element 106 at other suitable edge locations.

[0090] In the preferred embodiment, the posterior portion 104 includes adistending portion 132, preferably attached to the posterior viewingelement 118. The preferred distending portion 132 includes a firstdistending member 134 which in turn includes a fixed end 134 a, a freeend 134 b opposite the fixed end 134 a and preferably also includes anopening 134 c formed therein. The preferred distending portion 132 alsocomprises a second distending member 136 with a fixed end 136 a, a freeend 136 b and preferably an opening 136 c formed therein. In alternativeembodiments, the distending portion 132 may be omitted altogether, ormay comprise a single distending member or more than two distendingmembers. To optimize their effectiveness, the preferred location for thedistending members 134, 136 is 90 degrees away (about the optical axis)from the apices 112, 116 on the posterior portion 104. Where the biasingelements form more than two apices (or where two apices are not spaced180 degrees apart about the optical axis), one or more distendingmembers may be positioned angularly midway between the apices about theoptical axis. Alternatively, the distending member(s) may occupy othersuitable positions relative to the apices (besides the “angularlymidway” positions disclosed above); as further alternatives, thedistending member(s) may be located on the anterior portion 102 of thelens system 100, or even on the apices themselves. The functions of theretention portion 126 and the distending portion 132 will be describedin greater detail below.

III. The Lens System: Function/Optics

[0091] The anterior and posterior biasing elements 108, 120 function ina springlike manner to permit the anterior viewing element 106 andposterior viewing element 118 to move relative to each other generallyalong the optical axis. The biasing elements 108, 120 bias the viewingelements 106, 118 apart so that the elements 106, 108 separate to theaccommodated position or accommodated state shown in FIG. 4. Thus, inthe absence of any external forces, the viewing elements are at theirmaximum separation along the optical axis. The viewing elements 106, 118of the lens system 100 may be moved toward each other, in response to aciliary muscle force of up to 2 grams, to provide an unaccommodatedposition by applying appropriate forces upon the anterior and posteriorportions 102, 104 and/or the apices 112, 116.

[0092] When the lens system 100 is implanted in the capsular bag 58(FIGS. 16-17) the above described biasing forces cause the lens system100 to expand along the optical axis so as to interact with both theposterior and anterior aspects of the capsular bag. Such interactionoccurs throughout the entire range of motion of the ciliary muscle 60.At one extreme the ciliary muscle is relaxed and the zonules 62 pull thecapsular bag 58 radially so as to cause the bag to become more diskshaped. The anterior and posterior sides of the bag, in turn, applyforce to the anterior and posterior portions 102, 104 of the lens system100, thereby forcing the viewing elements 106, 118 toward each otherinto the accommodated position. At the other extreme, the ciliary musclecontracts and the zonules 62 move inwardly to provide slack in thecapsular bag 58 and allow the bag to become more football-shaped. Theslack in the bag is taken up by the lens system due to the biasing-apartof the anterior and posterior viewing elements 106, 118. As the radialtension in the bag is reduced, the viewing elements 106, 118 move awayfrom each other into an accommodated position. Thus, the distancebetween the viewing elements 106, 118 depends on the degree ofcontraction or relaxation of the ciliary muscle 60. As the distancebetween the anterior and posterior viewing elements 106, 118 is varied,the focal length of the lens system 100 changes accordingly. Thus, whenthe lens system 100 is implanted into the capsular bag (see FIGS. 16-17)the lens system 100 operates in conjunction with the naturalaccommodation processes of the eye to move between the accommodated(FIG. 16) and unaccommodated (FIG. 17) states in the same manner aswould a healthy “natural” lens. Preferably, the lens system 100 can movebetween the accommodated and unaccommodated states in less than aboutone second.

[0093] The lens system 100 has sufficient dynamic range that theanterior and posterior viewing elements 106, 118 move about 0.5-4 mm,preferably about 1-3 mm, more preferably about 1-2 mm, and mostpreferably about 1.5 mm closer together when the lens system 100 movesfrom the accommodated state to the unaccommodated state. In other wordsthe separation distance X (see FIGS. 9-10, 14-15) between the anteriorand posterior viewing elements 106, 118, which distance may for presentpurposes be defined as the distance along the optical axis (or aparallel axis) between a point of axial intersection with the posteriorface of the anterior viewing element 106 and a point of axialintersection with the anterior face of the posterior viewing element118, decreases by the amount(s) disclosed above upon movement of thelens system 100 to the unaccommodated state. Simultaneously, in thepreferred mode the total system thickness Y decreases from about 3.0-4.0mm in the accommodated state to about 1.5-2.5 mm in the unaccommodatedstate.

[0094] As may be best seen in FIG. 6, the first anterior translationmember 110 connects to the anterior viewing element 106 via connectionof the left and right arms 110 a, 110 b to first and second transitionmembers 138, 140 at attachment locations 142, 144. The second anteriortranslation member 114 connects to the anterior viewing element 106 viaconnection of left and right arms 114 a, 114 b to the first and secondtransition members 138, 140 at attachment locations 146, 148. This is apresently preferred arrangement for the first and second anteriortranslation members 110, 114; alternatively, the first and secondanterior translation members 110, 114 could be connected directly to theanterior viewing element 106, as is the case with the connection of thefirst and second posterior translation members 122, 124 to the posteriorviewing element 118.

[0095] However the connection is established between the first andsecond anterior translation members 110, 114 and the anterior viewingelement 106, it is preferred that the attachment locations 142, 144corresponding to the first anterior translation member 110 be fartheraway from the first apex 112 than is the closest edge or the peripheryof the anterior viewing element 106. This configuration increases theeffective length of the first anterior translation member 110/arms 110a, 110 b, in comparison to a direct or straight attachment between theapex 112 and the nearest/top edge of the anterior viewing element 106.For the same reasons, it is preferred that the attachment locations 146,148 associated with the second anterior translation member 114 befarther away from the second apex 116 than is the closest/bottom edge ofthe anterior viewing element 106.

[0096] As best seen in FIG. 7, the first posterior translation member122 is preferably connected directly to the posterior viewing element118 via attachment of the left and right arms 122 a, 122 b to theelement 118 at attachment points 150, 152. Likewise, the secondposterior translation member 124 is preferably directly connected to theposterior viewing element 118 via connection of the left and right arms124 a, 124 b to the element 118 at attachment points 154, 156,respectively. In alternative embodiments, the first and second posteriortranslation members 124, 122 can be connected to the posterior viewingelement via intervening members as is done with the anterior viewingelement 106. No matter how these connections are made, it is preferredthat the attachment locations 150, 152 be spaced further away from thefirst apex 112 than is the nearest edge or the periphery of theposterior viewing element 118. Similarly, it is preferred that theattachment locations 154, 156 be spaced further away from the secondapex 116 than is the closest edge of the posterior viewing element 118.

[0097] By increasing the effective length of some or all of thetranslation members 110, 114, 122, 124 (and that of the arms 110 a, 110b, 114 a, 114 b, 122 a, 122 b, 124 a, 124 b where such structure isemployed), the preferred configuration of the attachment locations 142,144, 146, 148, 150, 152, 154, 156 relative to the first and secondapices 112, 116 enables the anterior and/or posterior viewing elements106, 118 to move with respect to one another a greater distance alongthe optical axis, for a given angular displacement of the anteriorand/or posterior translation members. This arrangement thus facilitatesa more responsive spring system for the lens system 100 and minimizesmaterial fatigue effects associated with prolonged exposure to repeatedflexing.

[0098] In the illustrated embodiment, the attachment location 142 of thefirst anterior translation member 110 is spaced from the correspondingattachment location 146 of the second anterior translation member 114along the periphery of the anterior viewing element, and the samerelationship exists between the other pairs of attachment locations 144,148; 150, 154; and 152, 156. This arrangement advantageously broadensthe support base for the anterior and posterior viewing elements 106,118 and prevents them from twisting about an axis parallel to thelateral axis, as the viewing elements move between the accommodated andunaccommodated positions.

[0099] It is also preferred that the attachment locations 142, 144 ofthe first anterior translation member 110 be located equidistant fromthe first apex 112, and that the right and left arms 110 a, 110 b of themember 110 be equal in length. Furthermore, the arrangement of theattachment locations 146, 148, arms 114 a, 114 b and second apexpreferably mirrors that recited above regarding the first anteriortranslation member 110, while the apices 112, 116 are preferablyequidistant from the optical axis and are situated 180 degrees apart.This configuration maintains the anterior viewing element 106 orthogonalto the optical axis as the viewing element 106 moves back and forth andthe anterior viewing element flexes.

[0100] For the same reasons, a like combination of equidistance andequal length is preferred for the first and second posterior translationmembers 122, 124 and their constituent arms 122 a, 122 b, 124 a, 124 band attachment points 150, 152, 154, 156, with respect to the apices112, 116. However, as shown the arms 122 a, 122 b, 124 a, 124 b need notbe equal in length to their counterparts 110 a, 110 b, 114 a, 114 b inthe first and second anterior translation members 110, 114.

[0101] Where any member or element connects to the periphery of theanterior or posterior viewing elements 106, 118, the member defines aconnection geometry or attachment area with a connection width W and aconnection thickness T (see FIG. 4 and the example illustrated therein,of the connection of the second posterior translation member 124 to theposterior viewing element 118). For purposes of clarity, the connectionwidth is defined as being measured along a direction substantiallyparallel to the periphery of the viewing element in question, and theconnection thickness is defined as measured along a directionsubstantially perpendicular to the periphery of the viewing element.(The periphery itself is deemed to be oriented generally perpendicularto the optical axis as shown in FIG. 4.) Preferably, no attachment areaemployed in the lens system 100 has a ratio of width to thickness lessthan 3. It has been found that such a geometry reduces distortion of theviewing element/optic due to localized forces. For the same reasons, itis also preferred that each of the translation members 110, 114, 122,124 be connected to the periphery of the respective viewing elements atleast two attachment areas, each having the preferred geometry discussedabove.

[0102]FIGS. 17.1 and 17.2 show two preferred cross-sectionalconfigurations which may be used along some or all of the length of thetranslation members and/or arms 110 a, 110 b, 114 a, 114 b, 122 a, 122b, 124 a, 124 b. The shape is defined by a relatively broad and flat orslightly curved outer surface 182. It is intended that when in use theouter surface faces away from the interior of the lens system and/ortoward the capsular bag 58. The remaining surfaces, proportions anddimensions making up the cross-sectional shape can vary widely but mayadvantageously be selected to facilitate manufacture of the lens system100 via molding or casting techniques while minimizing stresses in thearms during use of the lens system.

[0103]FIG. 17.3 depicts a number of alternative cross-sectionalconfigurations which are suitable for the translation members and/orarms 110 a, 110 b, 114 a, 114 b, 122 a, 122 b, 124 a, 124 b. As shown, awide variety of cross-sectional shapes may be used, but preferably anyshape includes the relatively broad and flat or slightly curved outersurface 182.

[0104] It is further contemplated that the dimensions, shapes, and/orproportions of the cross-sectional configuration of the translationmembers and/or arms 110 a, 110 b, 114 a, 114 b, 122 a, 122 b, 124 a, 124b may vary along the length of the members/arms. This may be done inorder to, for example, add strength to high-stress regions of the arms,fine-tune their spring characteristics, add rigidity or flexibility,etc.

[0105] As discussed above, each of the anterior viewing element 106 andthe posterior viewing element 118 preferably comprises an optic havingrefractive power. In one preferred embodiment, the anterior viewingelement 106 comprises a biconvex lens having positive refractive powerand the posterior viewing element 118 comprises a convexo-concave lenshaving negative refractive power. The anterior viewing element 106 maycomprise a lens having a positive power advantageously less than 55diopters, preferably less than 40 diopters, more preferably less than 35diopters, and most preferably less than 30 diopters. The posteriorviewing element 118 may comprise a lens having a power which isadvantageously between −25 and 0 diopters, and preferably between −25and −15 diopters. In other embodiments, the posterior viewing element118 comprises a lens having a power which is between −15 and 0 diopters,preferably between −13 and −2 diopters, and most preferably between −10and −5 diopters. Advantageously, the total power of the optic(s)employed in the lens system 100 is about 5-35 diopters; preferably, thetotal power is about 10-30 diopters; most preferably, the total power isabout 15-25 diopters. (As used herein, the term “diopter” refers to lensor system power as measured when the lens system 100 has been implantedin the human eye in the usual manner.) It should be noted that ifmaterials having a high index of refraction (e.g., higher than that ofsilicone) are used, the optics may be made thinner which facilitates awider range of motion for the optics. This in turn allows the use oflower-power optics than those specified above. In addition, higher-indexmaterials allow the manufacture of a higher-power lens for a given lensthickness and thereby reduce the range of motion needed to achieve agiven range of accommodation.

[0106] Some lens powers and radii of curvature presently preferred foruse with an embodiment of the lens system 100 with optic(s) having arefractive index of about 1.432 are as follows: a +31 diopter, biconvexlens with an anterior radius of curvature of 5.944 mm and a posteriorradius of curvature of 5.944 mm; a +28 diopter, biconvex lens with ananterior radius of curvature of 5.656 mm and a posterior radius ofcurvature of 7.788 mm; a +24 diopter, biconvex lens with an anteriorradius of curvature of 6.961 mm and a posterior radius of curvature of8.5 mm; a −10 diopter, biconcave lens with an anterior radius ofcurvature of 18.765 mm and a posterior radius of curvature of 18.765 mm;a −8 diopter, concavo-convex lens with an anterior radius of curvatureof between 9 mm and 9.534 mm and a posterior radius of curvature of 40mm; and a −5 diopter, concavo-convex lens with an anterior radius ofcurvature of between 9 mm and 9.534 mm and a posterior radius ofcurvature of 20 mm. In one embodiment, the anterior viewing elementcomprises the +31 diopter lens described above and the posterior viewingelement comprises the −10 diopter lens described above. In anotherembodiment, the anterior viewing element comprises the +28 diopter lensdescribed above and the posterior viewing element comprises the −8diopter lens described above. In another embodiment, the anteriorviewing element comprises the +24 diopter lens described above and theposterior viewing element comprises the −5 diopter lens described above.

[0107] The combinations of lens powers and radii of curvature specifiedherein advantageously minimize image magnification. However, otherdesigns and radii of curvature provide modified magnification whendesirable.

[0108] The lenses of the anterior viewing element 106 and the posteriorviewing element 118 are relatively moveable as discussed above;advantageously, this movement is sufficient to produce an accommodationof at least one diopter, preferably at least two diopters and mostpreferably at least three diopters. In other words, the movement of theoptics relative to each other and/or to the cornea is sufficient tocreate a difference between (i) the refractive power of the user's eyein the accommodated state and (ii) the refractive power of the user'seye in the unaccommodated state, having a magnitude expressed indiopters as specified above. Where the lens system 100 has a singleoptic, the movement of the optic relative to the cornea is sufficient tocreate a difference in focal power as specified above.

[0109] Advantageously, the lens system 100 can be customized for anindividual patient's needs by shaping or adjusting only one of the fourlens faces, and thereby altering the overall optical characteristics ofthe system 100. This in turn facilitates easy manufacture andmaintenance of an inventory of lens systems with lens powers which willfit a large population of patients, without necessitating complexadjustment procedures at the time of implantation. It is contemplatedthat all of the lens systems in the inventory have a standardcombination of lens powers, and that a system is fitted to a particularpatient by simply shaping only a designated “variable” lens face. Thiscustom-shaping procedure can be performed to-order at a centralmanufacturing facility or laboratory, or by a physician consulting withan individual patient. In one embodiment, the anterior face of theanterior viewing element is the designated sole variable lens face. Inanother embodiment, the anterior face of the posterior viewing elementis the only variable face. However, any of the lens faces is suitablefor such designation. The result is minimal inventory burden withrespect to lens power (all of the lens systems in stock have the samelens powers) without requiring complex adjustment for individualpatients (only one of the four lens faces is adjusted in the fittingprocess).

IV. The System: Alternative Embodiments

[0110]FIG. 17.4 depicts another embodiment of the lens system 100 inwhich the anterior viewing element 106 comprises an optic with a smallerdiameter than the posterior viewing element 118, which comprises anoptic with a peripheral positive-lens portion 170 surrounding a centralnegative portion 172. This arrangement enables the user of the lenssystem 100 to focus on objects at infinity, by allowing the (generallyparallel) light rays incident upon the eye from an object at infinity tobypass the anterior viewing element 106. The peripheral positive-lensportion 170 of the posterior viewing element 118 can then function alonein refracting the light rays, providing the user with focused vision atinfinity (in addition to the range of visual distances facilitated bythe anterior and posterior viewing elements acting in concert). Inanother embodiment, the anterior viewing element 106 comprises an optichaving a diameter of approximately 3 millimeters or less. In yet anotherembodiment, the anterior viewing element 106 comprises an optic having adiameter of approximately 3 millimeters or less and a refractive powerof less than 55 diopters, more preferably less than 30 diopters. Instill another embodiment, the peripheral positive-lens portion 170 has arefractive power of about 20 diopters.

[0111]FIG. 17.5 shows an alternative arrangement in which, the anteriorviewing element 106 comprises an optic having a central portion 176 withrefractive power, and a surrounding peripheral region 174 having arefractive power of substantially zero, wherein the central region 176has a diameter smaller than the optic of the posterior viewing element118, and preferably has a diameter of less than about 3 millimeters.This embodiment also allows some incident light rays to pass theanterior viewing element (though the zero-power peripheral region 174)without refraction, allowing the peripheral positive-lens portion 170posterior viewing element 118 to function alone as described above.

[0112]FIGS. 18 and 19 depict another embodiment 250 of the intraocularlens. It is contemplated that, except as noted below, this embodiment250 is largely similar to the embodiment disclosed in FIGS. 3-17. Thelens 250 features an anterior biasing element 108 and posterior biasingelement 120 which are arranged asymmetrically as the lens system 100 isviewed from the side. As used herein to describe the biasing elements108, 120, “asymmetric” or “asymmetrically” means that, as the lenssystem 100 is viewed from the side, the first anterior translationmember 110 and the first posterior translation member 122 extend fromthe first apex 112 at unequal first anterior and posterior biasingangles δ₁, δ₂ with respect to the line B-B (which represents the edge ofa plane which is substantially orthogonal to the optical axis andintersects the first and second apices 112, 116) and/or that the secondanterior translation member 114 and the second posterior translationmember 124 extend from the second apex 116 at substantially equal secondanterior and posterior biasing angles δ₃, δ₄ with respect to the lineB-B.

[0113] In the embodiment shown in FIGS. 18-19, the first and secondanterior biasing angles δ₁, δ₃ are greater than the corresponding firstand second posterior biasing angles δ₂, δ₄. This arrangementadvantageously maintains the posterior viewing element 118 and apices112, 116 in a substantially stationary position. Consequently, themoving mass of the lens system 250 is reduced, and the anterior viewingelement 106 can move more quickly over a wider range along the opticalaxis under a given motive force. (Note that even where the posteriorbiasing element 120 and its constituent first and second posteriortranslation members 122, 124 are substantially immobile, they arenonetheless “biasing elements” and “translation members” as those termsare used herein.) In another embodiment, the anterior biasing element108 and posterior biasing element 120 are arranged asymmetrically in theopposite direction, i.e. such that the first and second anterior biasingangles δ₃, δ₃ are smaller than the corresponding first and secondposterior biasing angles δ₂, δ₄. This arrangement also provides for awider range of relative movement of the viewing elements, in comparisonto a “symmetric” system.

[0114] It should be further noted that the viewing elements 106, 118shown in FIGS. 18-19 are asymmetrically positioned in that the posteriorviewing element 118 is closer to the line B-B than is the anteriorviewing element 106. It has been found that this configuration yieldsdesirable performance characteristics irrespective of the configurationof the biasing elements 108, 120. In alternative embodiments, theviewing elements 106, 118 may be positioned symmetrically with respectto the line B-B, or they may be positioned asymmetrically with theanterior viewing element 106 closer to the line B-B than the posteriorviewing element 118 (see FIG. 4 wherein the line in question is denotedA-A). Furthermore, the symmetry or asymmetry of the biasing elements andviewing elements can be selected independently of each other.

[0115]FIG. 20 shows another embodiment 350 of an intraocular lens inwhich the posterior viewing element 118 comprises an annular framemember defining a void therein, while the anterior viewing element 106comprises an optic having refractive power. Alternatively, the posteriorviewing element 118 could comprise a zero power lens or a simpletransparent member. Likewise, in another embodiment the anterior viewingelement 106 could comprise an annular frame member with a void thereinor a simple zero power lens or transparent member, with the posteriorviewing element 118 comprising an optic having refractive power. As afurther alternative, one or both of the anterior and posterior viewingelements 106, 118 may comprise an annular or other perimeter framemember which can receive a removable optic (or a “one-time install”optic) with an interference type fit and/or subsequent adhesive orwelding connections. Such a configuration facilitates assembly and/orfine-tuning of the lens system during an implantation procedure, as willbe discussed in further detail below.

V. The System: Additional Features

[0116]FIG. 21 depicts the function of the distending portion 132 ingreater detail. The lens system 100 is shown situated in the capsularbag 58 in the customary manner with the anterior viewing element 106 andposterior viewing element 118 arranged along the optical axis. Thecapsular bag 58 is shown with a generally circular anterior opening 66which may often be cut into the capsular bag during installation of thelens system 100. The first and second distending members 134, 136 of thedistending portion 132 distend the capsular bag 58 so that intimatecontact is created between the posterior face of the posterior viewingelement and/or the posterior biasing element 120. In addition, intimatecontact is facilitated between the anterior face of the anterior viewingelement 106 and/or anterior biasing element 108. The distending members134, 136 thus remove any slack from the capsular bag 58 and ensureoptimum force coupling between the bag 58 and the lens system 100 as thebag 58 is alternately stretched and released by the action of theciliary muscle.

[0117] Furthermore, the distending members 134, 136 reshape the capsularbag 58 into a taller, thinner configuration along its range ofaccommodation to provide a wider range of relative motion of the viewingelements 106, 118. When the capsular bag 58 is in the unaccommodatedstate, the distending members 134, 136 force the capsular bag into athinner configuration (as measured along the optical axis) in comparisonto the unaccommodated configuration of the capsular bag 58 with thenatural lens in place. Preferably, the distending members 134, 136 causethe capsular bag 58 to taken on a shape in the unaccommodated statewhich is about 1.0-2.0 mm thinner, more preferably about 1.5 mm thinner,along the optical axis than it is with the natural lens in place and inthe unaccommodated state.

[0118] With such a thin “starting point” provided by the distendingmembers 134, 136, the viewing elements 106, 118 of the lens system canmove a greater distance apart, and provide a greater range ofaccommodation, without causing undesirable contact between the lenssystem and the iris. Accordingly, by reshaping the bag as discussedabove the distending members 134, 136 facilitate a range of relativemotion of the anterior and posterior viewing elements 106, 118 of about0.5-4 mm, preferably about 1-3 mm, more preferably about 1-2 mm, andmost preferably about 1.5 mm.

[0119] The distending portion 132/distending members 134, 136 arepreferably separate from the anterior and posterior biasing elements108, 120; the distending members 134, 136 thus preferably play no partin biasing the anterior and posterior viewing elements 106, 118 aparttoward the accommodated position. This arrangement is advantageousbecause the apices 112, 116 of the biasing elements 108, 120 reach theirpoint of minimum protrusion from the optical axis (and thus the biasingelements reach their minimum potential effectiveness for radiallydistending the capsular bag) when the lens system 100 is in theaccommodated state (see FIG. 16), which is precisely when the need isgreatest for a taut capsular bag so as to provide immediate response torelaxation of the ciliary muscles. The preferred distending portion is“static” (as opposed to the “dynamic” biasing members 108, 120 whichmove while urging the viewing elements 106, 118 to the accommodatedposition or carrying the viewing elements to the unaccommodatedposition) in that its member(s) protrude a substantially constantdistance from the optical axis throughout the range of motion of theviewing elements 106, 118. Although some degree of flexing may beobserved in the distending members 134, 136, they are most effectivewhen rigid. Furthermore, the thickness and/or cross-sectional profile ofthe distending members 134/136 may be varied over the length of themembers as desired to provide a desired degree of rigidity thereto.

[0120] The distending portion 132/distending members 132, 134advantageously reshape the capsular bag 58 by stretching the bag 58radially away from the optical axis and causing the bag 58 to take on athinner, taller shape throughout the range of accommodation by the eye.This reshaping is believed to facilitate a broad (as specified above)range of relative motion for the viewing elements of the lens system100, with appropriate endpoints (derived from the total systemthicknesses detailed above) to avoid the need for unacceptably thickoptic(s) in the lens system.

[0121] If desired, the distending members 134, 136 may also function ashaptics to stabilize and fixate the orientation of the lens system 100within the capsular bag. The openings 134 c, 136 c of the preferreddistending members 134,136 permit cellular ingrowth from the capsularbag upon positioning of the lens system 100 therein. Finally, othermethodologies, such as a separate capsular tension ring or the use ofadhesives to glue the capsular bag together in selected regions, may beused instead of or in addition to the distending portion 132, to reduce“slack” in the capsular bag.

[0122] A tension ring can also act as a physical barrier to cell growthon the inner surface of the capsular bag, and thus can provideadditional benefits in limiting posterior capsule opacification, bypreventing cellular growth from advancing posteriorly on the innersurface of the bag. When implanted, the tension ring firmly contacts theinner surface of the bag and defines a circumferential barrier againstcell growth on the inner surface from one side of the barrier toanother.

[0123]FIG. 21.1 shows an alternative configuration of the distendingportion 132, in which the distending members 134, 136 comprise first andsecond arcuate portions which connect at either end to the apices 112,116 to form therewith an integral perimeter member. In this arrangementit is preferred that the distending members and apices form an oval withheight I smaller than width J.

[0124]FIG. 21.2 shows another alternative configuration of thedistending portion 132, in which arcuate rim portions 137 interconnectthe apices 112, 116 and the free ends 134 b, 136 b of the distendingmembers 134, 136. Thus is formed an integral perimeter member withgenerally higher lateral rigidity than the arrangement depicted in FIG.21.1.

[0125]FIG. 21.3 shows another alternative configuration of thedistending portion 132, in which the distending members 134, 136 areintegrally formed with the first and second posterior translationmembers 122, 124. The distending members 134, 136 and translationmembers 122, 124 thus form common transition members 139 which connectto the periphery of the posterior viewing element 118.

[0126]FIG. 22 shows the function of the retention portion 126 in greaterdetail. It is readily seen that the first and second retention members128, 130 facilitate a broad contact base between the anterior portion ofthe lens system 100 and the anterior aspect of the capsular bag 58. Byappropriately spacing the first and second retention members 128, 130,the members prevent extrusion of the anterior viewing element 106through the anterior opening 66. It is also readily seen that wherecontact occurs between the anterior aspect of the capsular bag 58 andone or both of the retention members 128, 130, the retention membersalso participate in force coupling between the bag 58 and the lenssystem 100 as the bag is stretched and released by the action of theciliary muscles.

[0127] As best seen in FIGS. 21 and 22, the anterior portion 102 of thelens system 100 forms a number of regions of contact with the capsularbag 58, around the perimeter of the anterior viewing element 106. In theillustrated embodiment, at least some of these regions of contact arelocated on the anteriormost portions of the anterior biasing element108, specifically at the transition members 138, 140, and at theretention members 128, 130. The transition members and the retentionmembers define spaces therebetween at the edges of the anterior viewingelement 106 to permit fluid to flow between the interior of the capsularbag 58 and the portions of the eye anterior of the bag 58. In otherwords, the anterior portion of the lens system 100 includes at least onelocation which is spaced from and out of contact with the capsular bag58 to provide a fluid flow channel extending from the region between theviewing elements 106, 118 to the exterior of the bag 58. Otherwise, ifthe anterior portion 102 of the lens system 100 seals the anterioropening 66 of the bag 58, the resulting prevention of fluid flow cancause the aqueous humor in the capsular bag to stagnate, leading to aclinically adverse event, and can inhibit the movement of the lenssystem 100 between the accommodated and unaccommodated states.

[0128] If desired, one or both of the retention members 128, 130 mayhave an opening 129 formed therein to permit fluid flow as discussedabove. (See FIG. 21.1.)

[0129] The retention members 128, 130 and the transition members 138,140 also prevent contact between the iris and the anterior viewingelement 106, by separating the anterior opening 66 from the anteriorface of the viewing element 106. In other words, the retention members128, 130 and the transition members 138, 140 displace the anterioraspect of the capsular bag 58, including the anterior opening 66,anteriorly from the anterior viewing element 106, and maintain thisseparation throughout the range of accommodation of the lens system.Thus, if contact occurs between the iris and the lens system-capsularbag assembly, no part of the lens system will touch the iris, only thecapsular bag itself, in particular those portions of the bag 58overlying the retention members 128, 130 and/or the transition members138, 140. The retention members 128, 130 and/or the transition members138, 140 therefore maintain a separation between the iris and the lenssystem, which can be clinically adverse if the contacting portion(s) ofthe lens system are constructed from silicone.

[0130] As depicted in FIG. 22.1, one or more stop members 190 may belocated where appropriate on the anterior and/or posterior biasingelements 108, 120 to limit the convergent motion of the anterior andposterior viewing elements 106, 118, and preferably prevent contacttherebetween. As the lens system 100 moves toward the unaccommodatedposition, the stop member(s) located on the anterior biasing element 108come into contact with the posterior biasing element 120 (or withadditional stop member(s) located on thereon), and any stop member(s)located on the posterior biasing element 120 come into contact with theanterior biasing element 108 (or with additional stop member(s) locatedthereon). The stop members 190 thus define a point or state of maximumconvergence (in other words, the unaccommodated state) of the lenssystem 100/viewing elements 106, 118. Such definition advantageouslyassists in setting one extreme of the range of focal lengths which thelens system may take on (in those lens systems which include two or moreviewing elements having refractive power) and/or one extreme of therange of motion of the lens system 100.

[0131] The stop members 190 shown in FIG. 22.1 are located on the firstand second anterior translation members 110, 114 of the anterior biasingelement 108 and extend posteriorly therefrom. When the anterior andposterior viewing elements 106, 118 move together, one or more of thestop members 190 will contact the posterior translation member(s) 122,124, thereby preventing further convergent motion of the viewingelements 106, 118. Of course, in other embodiments the stop member(s)190 can be in any suitable location on the lens system 100.

VI. Mold Tooling

[0132] FIGS. 23-34 depict a mold system 500 which is suitable formolding the lens system 100 depicted in FIG. 3-17. The mold system 500generally comprises a first mold 502, a second mold 504 and a centermold 506. The center mold 506 is adapted to be positioned between thefirst mold 502 and the second mold 504 so as to define a mold space forinjection molding or compression molding the lens system 100. The moldsystem 500 may be formed from suitable metals, high-impact-resistantplastics or a combination thereof, and can be produced by conventionalmachining techniques such as lathing or milling, or by laser orelectrical-discharge machining. The mold surfaces can be finished ormodified by sand blasting, etching or other texturing techniques.

[0133] The first mold 502 includes a first mold cavity 508 with a firstanterior mold face 510 surrounded by an annular trough 512 and a firstperimeter mold face 514. The first mold 502 also includes a projection516 which facilitates easier mating with the second mold 504.

[0134] The center mold 506 includes a first center mold cavity 518 whichcooperates with the first mold cavity 508 to define a mold space forforming the anterior portion 102 of the lens system 100. The firstcenter mold cavity 518 includes a central anterior mold face 520 which,upon placement of the center mold 506 in the first mold cavity 508,cooperates with the first anterior mold face 510 to define a mold spacefor the anterior viewing element 106. In so doing, the first anteriormold face 510 defines the anterior face of the anterior viewing element106 and the central anterior mold face 520 defines the posterior face ofthe anterior viewing element 106. In fluid communication with thechamber formed by the first anterior mold face 510 and the centralanterior mold face 520 are lateral channels 522, 524 (best seen in FIG.31) which form spaces for molding the first and second transitionmembers 138, 140, along with the arms 110 a, 110 b of the first anteriortranslation member 110 as well as the arms 114 a, 114 b of the secondanterior translation member 114. The first center mold cavity 518 alsoincludes retention member cavities 526, 528 which define spaces formolding the first and second retention members 128, 130 to the anteriorviewing element 106.

[0135] The second mold 504 includes a second mold cavity 530 with asecond posterior mold space 532, a generally cylindrical transition 534extending therefrom and connecting to a second perimeter mold face 536.Lateral notches 538, 540 (best seen in FIGS. 26 and 27) are formed inthe second perimeter mold face 536. The second mold 504 also includes aninput channel 542 connected to an input channel opening 544 forintroducing material into the mold system 500. Also formed in the secondmold 504 is an output channel 546 and an output channel opening 548. Agenerally cylindrical rim 550 is included for mating with the projection516 of the first mold 502.

[0136] The center mold 506 includes a second center mold cavity 552which cooperates with the second mold cavity 530 to define a mold spacefor the posterior portion 104 of the lens system 100. The second centermold cavity 552 includes a central posterior mold face 554 which, uponplacement of the center mold 506 in engagement with the second moldcavity 530, cooperates with the second posterior mold face 532 and thetransition 534 to define a chamber for forming the posterior viewingelement 118. In fluid communication with the chamber formed by thecentral posterior mold face 554 and the second posterior mold face 532are lateral channels 556, 558, 560, 562 which provide a mold space forforming the arms 122 a, 122 b of the first posterior translation member122 and the arms 124 a, 124 b of the second posterior translation member124. The second center mold cavity 552 includes lateral projections 564,566 which coact with the notches 538, 540 formed in the second moldcavity 530. The chambers formed therebetween are in fluid communicationwith the chamber defined by the central posterior mold face 554 and thesecond posterior mold face 532 to form the first and second distendingmembers 134, 136 integrally with the posterior viewing element 118.

[0137] The center mold 506 includes a first reduced-diameter portion 568and a second reduced-diameter portion 570 each of which, upon assemblyof the mold system 500, defines a mold space for the apices 112, 116 ofthe lens system 100.

[0138] In use, the mold system 500 is assembled with the center mold 506positioned between the first mold 502 and the second mold 504. Onceplaced in this configuration, the mold system 500 is held together underforce by appropriate techniques, and lens material is introduced intothe mold system 500 via the input channel 542. The lens material thenfills the space defined by the first mold 502, second mold 504, and thecenter mold 506 to take on the shape of the finished lens system 100.

[0139] In another embodiment, the lens system 100 or a portion thereofis formed by a casting or liquid-casting procedure in which one of thefirst or second molds is first filled with a liquid and the center moldis placed then into engagement with the liquid-filled mold. The exposedface of the center mold is then filled with liquid and the other of thefirst and second molds is placed into engagement with the rest of themold system. The liquid is allowed or caused to set/cure and a finishedcasting may then removed from the mold system.

[0140] The mold system 500 can advantageously be employed to produce alens system 100 as a single, integral unit. Alternatively, variousportions of the lens system 100 can be separately molded, casted,machined, etc. and subsequently assembled to create a finished lenssystem. Assembly can be performed as a part of centralized manufacturingoperations; alternatively, a physician can perform some or all of theassembly before or during the implantation procedure, to select lenspowers, biasing members, system sizes, etc. which are appropriate for aparticular patient.

[0141] The center mold 506 is depicted as comprising an integral unitwith first and second center mold cavities 518, 552. Alternatively, thecenter mold 506 may have a modular configuration whereby the first andsecond mold cavities 518, 552 may be interchangeable to adapt the centermold 506 for manufacturing a lens system 100 according to a desiredprescription or specification, or to otherwise change the power(s) ofthe lenses made with the mold. In this manner the manufacture of a widevariety of prescriptions may be facilitated by a set of mold cavitieswhich can be assembled back-to-back or to opposing sides of a main moldstructure.

VII. Materials/Surface Treatments

[0142] Preferred materials for forming the lens system 100 includesilicone, acrylics, polymethylmethacrylate (PMMA), block copolymers ofstyrene-ethylene-butylene-styrene (C-FLEX) or other styrene-basecopolymers, polyvinyl alcohol (PVA), polyurethanes, hydrogels or anyother suitable polymers or monomers. In addition, any portion of thelens system 100 other than the optic(s) may be formed from stainlesssteel or a shape-memory alloy such as nitinol or any iron-basedshape-memory alloy. Metallic components may be coated with gold toincrease biocompatibility. Where feasible, material of a lower Shore Ahardness such as 15A may be used for the optic(s), and material ofhigher hardness such as 35A may be used for the balance of the lenssystem 100. Finally, the optic(s) may be formed from a photosensitivesilicone to facilitate post-implantation power adjustment as taught inU.S. patent application Ser. No. 09/416,044, filed Oct. 8, 1999, titledLENSES CAPABLE OF POST-FABRICATION POWER MODIFICATION, the entirecontents of which are hereby incorporated by reference herein.

[0143] Methyl-methylacrylate monomers may also be blended with any ofthe non-metallic materials discussed above, to increase the lubricity ofthe resulting lens system (making the lens system easier to fold or rollfor insertion, as discussed further below). The addition ofmethyl-methylacrylate monomers also increases the strength andtransparency of the lens system.

[0144] The optics and/or the balance of the lens system 100 can also beformed from layers of differing materials. The layers may be arranged ina simple sandwich fashion, or concentrically. In addition, the layersmay include a series of polymer layers, a mix of polymer and metalliclayers, or a mix of polymer and monomer layers. In particular, a nitinolribbon core with a surrounding silicone jacket may be used for anyportion of the lens system 100 except for the optics; anacrylic-over-silicone laminate may be employed for the optics. A layeredconstruction may be obtained by pressing/bonding two or more layerstogether, or deposition or coating processes may be employed.

[0145] In one embodiment, portions of the lens system 100 other than theoptic(s) are formed from a shape-memory alloy. This embodiment takesadvantage of the exceptional mechanical properties of shape-memoryalloys and provides fast, consistent, highly responsive movement of theoptic(s) within the capsular bag while minimizing material fatigue inthe lens system 100. In one embodiment, one or both of the biasingelements 108, 120 are formed from a shape-memory alloy such as nitinolor any iron-based shape-memory alloy. Due to the flat stress-straincurve of nitinol, such biasing elements provide a highly consistentaccommodation force over a wide range of displacement. Furthermore,biasing elements formed from a shape-memory alloy, especially nitinol,retain their spring properties when exposed to heat (as occurs uponimplantation into a human eye) while polymeric biasing elements tend tolose their spring properties, thus detracting from the responsiveness ofthe lens system. For similar reasons, it is advantageous to useshape-memory alloys such as those discussed above in forming any portionof a conventional (non-accommodating) intraocular lens, other than theoptic.

[0146] Where desired, various coatings are suitable for components ofthe lens system 100. A heparin coating may be applied to appropriatelocations on the lens system 100 to prevent inflammatory cell attachment(ICA) and/or posterior capsule opacification (PCO); naturally, possiblelocations for such a coating include the posterior biasing element 120and the posterior face of the posterior viewing element 118. Coatingscan also be applied to the lens system 100 to improve biocompatibility;such coatings include “active” coatings like P-15 peptides or RGDpeptides, and “passive” coatings such as heparin and othermucopolysaccharides, collagen, fibronectin and laminin. Other coatings,including hirudin, teflon, teflon-like coatings, PVDF, fluorinatedpolymers, and other coatings which are inert relative to the capsularbag may be employed to increase lubricity at locations (such as theoptics and distending members) on the lens system which contact the bag,or Hema or silicone can be used to impart hydrophilic or hydrophobicproperties to the lens system 100.

[0147] It is also desirable subject the lens system 100 and/or the moldsurfaces to a surface passivation process to improve biocompatibility.This may be done via conventional techniques such as chemical etching orplasma treatment.

[0148] Furthermore, appropriate surfaces (such as the outeredges/surfaces of the viewing elements, biasing elements, distendingmembers, retention members, etc.) of the lens system 100 can be texturedor roughened to improve adhesion to the capsular bag. This may beaccomplished by using conventional procedures such as plasma treatment,etching, dipping, vapor deposition, mold surface modification, etc. As afarther means of preventing ICA/PCO, a posteriorly-extending perimeterwall (not shown) may be added to the posterior viewing element 118 so asto surround the posterior face of the posterior optic. The wall firmlyengages the posterior aspect of the capsular bag and acts as a physicalbarrier to the progress of cellular ingrowth occurring on the interiorsurface of the capsular bag. Finally, the relatively thick cross-sectionof the preferred anterior viewing element 118 (see FIGS. 9, 10) ensuresthat it will firmly abut the posterior capsule with no localizedflexing. Thus, with its relatively sharp rim, the posterior face of thepreferred posterior viewing element 118 can itself serve-as a barrier tocellular ingrowth and ICA/PCO. In order to achieve this effect, theposterior viewing element 118 is preferably made thicker thanconventional intraocular lenses. As an alternative or supplement to athick posterior viewing element, cell growth may be inhibited by forminga pronounced, posteriorly-extending perimeter rim on the posterior faceof the posterior viewing element 118. Upon implantation of the lenssystem 100, the rim firmly abuts the inner surface of the capsular bag58 and acts as a physical barrier to cell growth between the posteriorface of the posterior viewing element 118 and the capsular bag 58.

[0149] The selected material and lens configuration should be able towithstand secondary operations after molding/casting such as polishing,cleaning and sterilization processes involving the use of an autoclave,or ethylene oxide or radiation. After the mold is opened, the lensshould undergo deflashing, polishing and cleaning operations, whichtypically involve a chemical or mechanical process, or a combinationthereof. Suitable mechanical processes include tumbling, shaking andvibration; a tumbling process may involve the use of a barrel withvarying grades of glass beads, fluids such as alcohol or water andpolishing compounds such as aluminum oxides. Process rates are materialdependent; for example, a tumbling process for silicone should utilize a6″ diameter barrel moving at 30-100 RPM. It is contemplated that severaldifferent steps of polishing and cleaning may be employed before thefinal surface quality is achieved.

[0150] In one embodiment, the lens system 100 is held in a fixture toprovide increased separation between, and improved process effect on,the anterior and posterior viewing elements during thedeflashing/polishing/cleaning operations. In another embodiment, thelens system 100 is everted or turned “inside-out” so that the innerfaces of the viewing elements are better exposed during a portion of thedeflashing/polishing/cleaning. FIG. 34.1 shows a number of expansiongrooves 192 which may be formed in the underside of the apices 112, 116of the lens system 100 to facilitate eversion of the lens system 100without damaging or tearing the apices or the anterior/posterior biasingelements 108, 120. For the same reasons similar expansion grooves may beformed on the opposite sides (i.e., the outer surfaces) of the apices112, 116 instead of or in addition to the location of grooves on theunderside.

[0151] A curing process may also be desirable in manufacturing the lenssystem 100. If the lens system is produced from silicone entirely atroom temperature, the curing time can be as long as several days. If themold is maintained at about 50 degrees C., the curing time is reduced toabout 24 hours; if the mold is preheated to 100-200 degrees C. thecuring time can be as short as about 3-15 minutes. Of course, thetime-temperature combinations vary for other materials.

VIII. Multiple-piece and Other Embodiments

[0152]FIG. 35 is a schematic view of a two-piece embodiment 600 of thelens system. In this embodiment the anterior portion 102 and theposterior portion 104 are formed as separate pieces which are intendedfor separate insertion into the capsular bag and subsequent assemblytherein. In one embodiment, each of the anterior and posterior portions102, 104 is rolled or folded before insertion into the capsular bag.(The insertion procedure is discussed in further detail below.) Theanterior portion 102 and posterior portion 104 are representedschematically as they may generally comprise any anterior-portion orposterior-portion structure disclosed herein; for example, they maysimply comprise the lens system 100 shown in FIGS. 3-17, bisected alongthe line/plane A-A shown in FIG. 4. The anterior portion 102 andposterior portion 104 of the two-piece lens system 600 will includefirst and second abutments 602, 604 which are intended to be placed inabutting relation (thus forming the first and second apices of the lenssystem) during the assembly procedure. The first and second abutments602, 604 may include engagement members (not shown), such as matchingprojections and recesses, to facilitate alignment and assembly of theanterior and posterior portions 102, 104.

[0153] As a further alternative, the anterior and posterior portions102, 104 of the lens system 600 may be hingedly connected at one of theabutments 602, 604 and unconnected at the other, to allow sequential(but nonetheless partially assembled) insertion of the portions 102, 104into the capsular bag. The individual portions may be separately rolledor folded before insertion. The two portions 102, 104 are “swung”together and joined at the unconnected abutment to form the finishedlens system after both portions have been inserted and allowed tounfold/unroll as needed.

[0154]FIG. 36 depicts schematically another embodiment 700 of atwo-piece lens system. The lens system 700 is desirably similar to thelens system 600 shown in FIG. 35, except for the formation of relativelylarger, curled abutments 702, 704 which are assembled to form the apices112, 116 of the system 700.

[0155]FIGS. 37 and 38 show a further embodiment 800 of the lens system,in which the anterior and posterior biasing elements 108, 120 compriseintegral “band” like members forming, respectively, the first and secondanterior translation members 110, 114 and the first and second posteriortranslation members 122, 124. The biasing elements 108, 120 also formreduced-width portions 802, 804 which meet at the apices of the lenssystem 800 and provide regions of high flexibility to facilitatesufficient accommodative movement. The depicted distending portion 132includes three pairs of distending members 134, 136 which have a curvedconfiguration but nonetheless project generally away from the opticalaxis.

[0156]FIGS. 38.1 and 38.2 depict another embodiment 900 of the lenssystem, as implanted in the capsular bag 58. The embodiment shown inFIGS. 38.1 and 38.2 may be similar to any of the embodiments describedabove, except that the biasing elements 108, 120 are dimensioned so thatthe apices 112, 116 abut the zonules 62 and ciliary muscles 60 when inthe unaccommodated state as seen in FIG. 38.1. In addition, the lenssystem 900 is configured such that it will remain in the unaccommodatedstate in the absence of external forces. Thus, when the ciliary muscles60 contract, the muscles 60 push the apices 112, 116 closer together,causing the biasing elements 108, 120 to bow out and the viewingelements 106, 118 to separate and attain the accommodated state as shownin FIG. 38.2. When the ciliary muscles 60 relax and reduce/eliminate theforce applied to the apices 112, 116 the biasing elements 108, 120 movethe lens system 900 to the unaccommodated state depicted in FIG. 38.1.

[0157]FIGS. 38.3 and 38.4 depict biasers 1000 which may be used bias thelens system 100 toward the accommodated or unaccommodated state,depending on the desired operating characteristics of the lens system.It is therefore contemplated that the biasers 1000 may be used with anyof the embodiments of the lens system 100 disclosed herein. The biasprovided by the biasers 1000 may be employed instead of, or in additionto, any bias generated by the biasing elements 108, 120. In oneembodiment (see FIG. 38.3), the biasers 1000 may comprise U-shapedspring members having apices 1002 located adjacent the apices 112, 116of the lens system 100. In another embodiment (see FIG. 38.4), thebiasers 1000 may comprise any suitable longitudinal-compression springswhich span the apices 112, 116 and interconnect the anterior andposterior biasing elements 108, 120. By appropriately selecting thespring constants and dimensions of the biasers 1000 (in the case ofU-shaped springs, the apex angle and arm length; in the case oflongitudinal-compression springs, their overall length), the biasers1000 can impart to the lens system 100 a bias toward the accommodated orunaccommodated state as desired.

[0158] The biasers 1000 may be formed from any of the materialsdisclosed herein as suitable for constructing the lens system 100itself. The material(s) selected for the biasers 1000 may be the sameas, or different from, the material(s) which are used to form theremainder of the particular lens system 100 to which the biasers 1000are connected. The number of biasers 1000 used in a particular lenssystem 100 may be equal to or less than the number of apices formed bythe biasing elements of the lens system 100.

IX. Implantation Methods

[0159] Various techniques may be employed in implanting the variousembodiments of the lens system in the eye of a patient. The physiciancan first access the anterior aspect of the capsular bag 58 via anyappropriate technique. Next, the physician incises the anterior of thebag; this may involve making the circular opening 66 shown in FIGS. 21and 22, or the physician may make a “dumbbell” shaped incision byforming two small circular incisions or openings and connecting themwith a third, straight-line incision. The natural lens is then removedfrom the capsular bag via any of various known techniques, such asphacoemulsification, cryogenic and/or radiative methods. To inhibitfurther cell growth, it is desirable to remove or kill all remainingepithelial cells. This can be achieved via cryogenic and/or radiativetechniques, antimetabolites, chemical and osmotic agents. It is alsopossible to administer agents such as P15 to limit cell growth bysequestering the cells.

[0160] In the next step, the physician implants the lens system into thecapsular bag. Where the lens system comprises separate anterior andposterior portions, the physician first folds or rolls the posteriorportion and places it in the capsular bag through the anterior opening.After allowing the posterior portion to unroll/unfold, the physicianadjusts the positioning of the posterior portion until it is withinsatisfactory limits. Next the physician rolls/folds and implants theanterior portion in a similar manner, and aligns and assembles theanterior portion to the posterior portion as needed, by causingengagement of mating portions, etc. formed on the anterior and posteriorportions.

[0161] Where the lens system comprises anterior and posterior portionswhich are partially assembled or partially integral (see discussionabove in the section titled MULTIPLE-PIECE AND OTHER EMBODIMENTS), thephysician employs appropriate implantation procedures, subsequentlyfolding/rolling and inserting those portions of the lens system that areseparately foldable/rollable. In one embodiment, the physician firstrolls/folds one portion of the partially assembled lens system and theninserts that portion. The physician then rolls/folds another portion ofthe partially assembled lens system and the inserts that portion. Thisis repeated until the entire system is inside the capsular bag,whereupon the physician completes the assembly of the portions andaligns the lens system as needed. In another embodiment, the physicianfirst rolls/folds all of the separately rollable/foldable portions ofthe partially assembled lens system and then inserts the rolled/foldedsystem into the capsular bag. Once the lens system is in the capsularbag, the physician completes the assembly of the portions and aligns thelens system as needed.

[0162] It is contemplated that conventional intraocular lens foldingdevices, injectors, syringes and/or shooters can be used to insert anyof the lens systems disclosed herein. A preferred folding/rollingtechnique is depicted in FIG. 39, where the lens system 100 is shownfirst in its normal condition (A). The anterior and posterior viewingelements 106, 118 are manipulated to place the lens system 100 in alow-profile condition (B), in which the viewing elements 106, 118 areout of axial alignment and are preferably situated so that no portion ofthe anterior viewing element 106 overlaps any portion of the posteriorviewing element 118, as viewed along the optical axis. In thelow-profile position (B), the thickness of the lens system 100 isminimized because the viewing elements 106, 118 are not “stacked” on topof each other, but instead have a side-by-side configuration. From thelow-profile condition (B) the viewing elements 106, 118 and/or otherportions of the lens system 100 can be folded or rolled generally aboutthe transverse axis, or an axis parallel thereto. Alternatively, thelens system could be folded or rolled about the lateral axis or an axisparallel thereto. Upon folding/rolling, the lens system 100 is placed ina standard insertion tool as discussed above and is inserted into theeye.

[0163] When the lens system 100 is in the low-profile condition (B), thesystem may be temporarily held in that condition by the use ofdissolvable sutures, or a simple clip which is detachable ormanufactured from a dissolvable material. The sutures or clip hold thelens system in the low-profile condition during insertion and for adesired time after insertion. By temporarily holding the lens system inthe low-profile condition after insertion, the sutures or clip providetime for fibrin formation on the edges of the lens system which, afterthe lens system departs from the low-profile condition, mayadvantageously bind the lens system to the inner surface of the capsularbag.

[0164] The physician next performs any adjustment steps which arefacilitated by the particular lens system being implanted. Where thelens system is configured to receive the optic(s) in “open” framemembers, the physician first observes/measures/determines thepost-implantation shape taken on by the capsular bag and lens system inthe accommodated and/or unaccommodated states and select(s) the opticswhich will provide the proper lens-system performance in light of theobserved shape characteristics and/or available information on thepatient's optical disorder. The physician then installs the optic(s) inthe respective frame member(s); the installation takes place either inthe capsular bag itself or upon temporary removal of the neededportion(s) of the lens system from the bag. If any portion is removed, afinal installation and assembly is then performed with the optic(s) inplace in the frame member(s).

[0165] Where the optic(s) is/are formed from an appropriatephotosensitive silicone as discussed above, the physician illuminatesthe optic(s) (either anterior or posterior or both) with an energysource such as a laser until they attain the needed physical dimensionsor refractive index. The physician may perform an intervening step ofobserving/measuring/determining the post-implantation shape taken on bythe capsular bag and lens system in the accommodated and/orunaccommodated states, before determining any needed changes in thephysical dimensions or refractive index of the optic(s) in question.

[0166]FIG. 40 depicts a technique which may be employed during lensimplantation to create a fluid flow path between the interior of thecapsular bag 58 and the region of the eye anterior of the capsular bag58. The physician forms a number of fluid-flow openings 68 in theanterior aspect of the capsular bag 58, at any desired location aroundthe anterior opening 66. The fluid-flow openings 68 ensure that thedesired flow path exists, even if a seal is created between the anterioropening 66 and a viewing element of the lens system.

[0167] Where an accommodating lens system is implanted, the openings 68create a fluid flow path from the region between the viewing elements ofthe implanted lens system, and the region of the eye anterior of thecapsular bag 58. However, the technique is equally useful for use withconventional (non-accommodating) intraocular lenses.

[0168] Although this invention has been disclosed in the context ofcertain preferred embodiments and examples, it will be understood bythose skilled in the art that the present invention extends beyond thespecifically disclosed embodiments to other alternative embodimentsand/or uses of the invention and obvious modifications and equivalentsthereof. Thus, it is intended that the scope of the present inventionherein disclosed should not be limited by the particular disclosedembodiments described above, but should be determined only by a fairreading of the claims that follow.

What is claimed is:
 1. An accommodating intraocular lens forimplantation in an eye having a lens capsule and an optical axis, saidlens comprising: an anterior portion comprised of a viewing element,said viewing element comprised of an optic having refractive power; aposterior portion comprised of a viewing element, said viewing elementsmounted to move relative to each other along the optical axis inresponse to force generated by the ciliary muscle of the eye; adistending portion comprised of a first distending member having a fixedend attached to one of the anterior portion and the posterior portion,and a free end sized and oriented to distend a portion of the lenscapsule such that coupling of forces between the lens capsule and theintraocular lens is modified by said distending portion.
 2. The lens ofclaim 1, wherein said distending portion further comprises a seconddistending member having a fixed end attached to one of the anteriorportion and the posterior portion, and a free end sized and oriented todistend a portion of the lens capsule.
 3. The lens of claim 2, wherein:said lens includes an optical axis which is adapted to be substantiallycoincident with the optical axis of the eye upon implantation of saidlens; and said first and second distending portions are attached to saidviewing element of said posterior portion and are arranged 180 degreesapart about said optical axis of said lens.
 4. The lens of claim 1,wherein said first distending member further comprises an opening topermit cellular ingrowth by adjacent portions of the lens capsule. 5.The lens of claim 1, wherein: said lens includes an optical axis whichis adapted to be substantially coincident with the optical axis of theeye upon implantation of said lens; said anterior portion furthercomprises an anterior biasing element and said posterior portion furthercomprises a posterior biasing element, said biasing elements beingjoined at first and second apices which are spaced from said opticalaxis of said lens; and said first distending member is located angularlymidway between said apices about said optical axis of said lens.
 6. Thelens of claim 5, wherein: said distending portion further comprises asecond distending member having a fixed end attached to one of theanterior portion and the posterior portion, and a free end sized andoriented to distend a portion of the lens capsule; and said seconddistending member is located angularly midway between said apices aboutsaid optical axis of said lens and is arranged 180 degrees away fromsaid first distending member about said optical axis of said lens. 7.The lens of claim 1, wherein: said lens includes an optical axis whichis adapted to be substantially coincident with the optical axis of theeye upon implantation of said lens; and said free end of said firstdistending member is adapted to remain at a substantially constantdistance from said optical axis as said viewing elements move relativeto each other.
 8. The lens of claim 1, wherein: said lens includes anoptical axis which is adapted to be substantially coincident with theoptical axis of the eye upon implantation of said lens; said anteriorportion further comprises an anterior biasing element and said posteriorportion further comprises a posterior biasing element, said biasingelements being joined at first and second apices which are spaced fromsaid optical axis of said lens; and said lens further comprises at leastone rim member extending from one of said first and second apices tosaid free end of said first distending member.
 9. The lens of claim 8,wherein: said distending portion further comprises a second distendingmember having a fixed end attached to one of the anterior portion andthe posterior portion, and a free end sized and oriented to distend aportion of the lens capsule; and said lens further comprises at leastone rim member extending from one of said first and second apices tosaid free end of said second distending member.
 10. The lens of claim 9,further comprising rim members extending from said first apex to saidfree ends of said first and second distending members, and from saidsecond apex to said free ends of said first and second distendingmembers.
 11. An accommodating intraocular lens for implantation in aneye having an optical axis, said lens comprising: an anterior portioncomprised of an anterior viewing element and an anterior biasing elementconnected to said anterior viewing element, said anterior viewingelement comprised of an optic having refractive power; a posteriorportion comprised of a posterior viewing element and a posterior biasingelement connected to said posterior viewing element; an optical axis ofsaid lens which is adapted to be substantially coincident with theoptical axis of the eye upon implantation of said lens; said anteriorand posterior viewing elements mounted to move relative to each otheralong the optical axis in response to force generated by the ciliarymuscle of the eye, said biasing elements being joined at first andsecond apices which are spaced from said optical axis of said lens; adistending member extending between said first and second apices. 12.The lens of claim 11, wherein said distending member comprises anarcuate portion extending between said first and second apices.
 13. Thelens of claim 12, wherein said distending member comprises first andsecond arcuate portions extending between said first and second apiceson either side of said lens.
 14. The lens of claim 13, wherein saidfirst and second arcuate portions define a width of said lens and saidfirst and second apices defining a height of said lens, said width beinglarger than said height.
 15. An accommodating intraocular lens forimplantation in an eye having a lens capsule and an optical axis, saidlens comprising: an anterior portion comprised of a viewing element,said viewing element comprised of an optic having refractive power; aposterior portion comprised of a viewing element, said viewing elementsmounted to move relative to each other along the optical axis inresponse to force generated by the ciliary muscle of the eye; adistending portion comprised of a distending member attached to one ofsaid portions, and oriented to distend the lens capsule such that thedistance between a posterior side of the posterior viewing element andan anterior side of the anterior viewing element along the optical axisis less than 3 mm when the ciliary muscle is relaxed and the lens is inan unaccommodated state.
 16. An accommodating intraocular lens forimplantation in an eye having a lens capsule and an optical axis, saidlens comprising: an anterior portion comprised of a viewing element,said viewing element comprised of an optic having refractive power; aposterior portion comprised of a viewing element, said viewing elementsmounted to move relative to each other along the optical axis inresponse to force generated by the ciliary muscle of the eye; adistending portion comprised of a distending member attached to one ofsaid portions, and oriented to distend the lens capsule, said distendingcausing said lens capsule to act on at least one of the posterior andanterior portions such that separation between said viewing elements isreduced when the ciliary muscle is relaxed and the lens is in anunaccommodated state.
 17. An accommodating intraocular lens forimplantation in an eye having a lens capsule and an optical axis, saidlens comprising: an anterior portion comprised of a viewing element,said viewing element comprised of an optic having refractive power; aposterior portion comprised of a viewing element, said viewing elementsmounted to move relative to each other along the optical axis inresponse to force generated by the ciliary muscle of the eye; adistending member attached to the posterior portion, said distendingmember separate from said biasing members and reshaping the lens capsulesuch that force coupling between the ciliary muscle and the lens ismodified to provide greater relative movement between said viewingelements when the lens moves between an unaccommodated state and anaccommodated state in response to said ciliary muscle.
 18. Anaccommodating intraocular lens for implantation in an eye having anoptical axis, said lens comprising: an anterior portion comprised of ananterior viewing element and an anterior biasing element connected tosaid anterior viewing element, said anterior viewing element comprisedof an optic having refractive power; a posterior portion comprised of aposterior viewing element and a posterior biasing element connected tosaid posterior viewing element; an optical axis of said lens which isadapted to be substantially coincident with the optical axis of the eyeupon implantation of said lens; said anterior and posterior viewingelements mounted to move relative to each other along the optical axisin response to force generated by the ciliary muscle of the eye, saidbiasing elements being joined at first and second apices which arespaced from said optical axis of said lens; first and second distendingmembers, each of said members attached to one of said anterior andposterior portions and extending away from the optical axis, said firstmember disposed between said apices on one side of the intraocular lensand said second member disposed between said apices on the opposite sideof the intraocular lens, said distending members oriented to distendportions of the lens capsule such that said viewing elements arerelatively movable through a range of at least 1.0 mm in response tocontraction of said ciliary muscle.
 19. An accommodating intraocularlens for implantation in an eye having an optical axis, said lenscomprising: an anterior portion comprised of a viewing element, saidanterior viewing element comprised of an optic having a diameter ofapproximately 3 mm or less and a refractive power of less than 55diopters; a posterior portion comprised of a viewing element, saidviewing elements mounted to move relative to each other along theoptical axis in response to force generated by the ciliary muscle of theeye; a distending portion comprised of a distending member having afixed end attached to the posterior portion and a free end sized andoriented to distend a portion of the lens capsule such that coupling offorces between the lens capsule and the intraocular lens is increased.20. A method comprising: implanting an accommodating intraocular lenshaving anterior and posterior portions that are biased apart, saidimplanting comprising placing said lens in a lens capsule of an eye andreshaping the lens capsule by applying a distending force thereto, saidreshaping comprising tensioning at least a portion of the capsularmembrane to cause the capsule to draw the anterior and posteriorportions towards each other at least when the ciliary muscle of the eyeis relaxed and the accommodating lens is in an unaccommodated state. 21.The method of claim 20, wherein said tensioning comprises applying adistending force only to the posterior side of the lens capsule.